Oily waxcap - Hygrocybe quieta

A very variable species.  The gap is dry/slightly greasy, yellow but drying paler; mature specimens may have a greyish tinge to the cap.  The stipe is yellow, often with an orange tinge especially to the top; gill attachment is variable, but the gills are usually yellow-orange with a pinkish tinge.  The most distinctive feature is the unpleasant smell, descibed by some sources as like bed-bugs or wet laundry; by others like oily fish; best detected by crushing gills or placing in a sealed container for a while. Specimens are often larger than other yellow waxcaps, and crumble apart easily; the mature caps often split. 

other yellow waxcap species

Side top and underneath photos; note the dimensions or photograph with a ruler or other object as a size reference, or in your hand.  You must note the smell.

old grasslands, usually with moss: lawns, cemeteries, churchyards and mown or grazed unimproved grassland

October-November

common

Not known; probably occasional in suitable habitats, but under-recorded